Although previous reports suggested that the quality of food supplies is declining, these reports used data that did not specify the varieties grown or the environments used for each crop’s production, according to Dr. Michael Grusak, USDA/ARS plant physiologist and professor of pediatrics at BCM, who served as co-author of the paper.
“We know that the environment has a big impact on the nutritional quality of foods,” said Grusak. “We decided to go as far back as we could with available varieties of broccoli and grow them in the same environment, in the same fields and test their nutritional value for minerals to see if there was a longitudinal decline in nutritional quality.”
All 14 varieties of broccoli were grown at the same time in the same environment in South Carolina.
Researchers analyzed essential minerals including calcium, magnesium, potassium, phosphorous, iron, zinc as well as others. These minerals are the building blocks of the body’s tissues and regulate metabolic activity at the cellular level.
Grusak and colleagues found no downward trend in nutritional value of commercially available broccoli.
“We know that even though breeders have changed and improved the way in which broccoli is grown over the years, there has been no change in the mineral quality of broccoli,” said Grusak. “This data can be a useful guide in the future for breeders so they can maintain this level of mineral quality.”
Others who took part in the study include Mark W. Farnham with the USDA/ARS and Anthony P. Keinath at Clemson University.
Funding for this study came from the U.S. Department of Agriculture – Agricultural Research Service.